Normal roof structures of the inverted V-shape have a tendency to spread at the lower ends of the roof sheets where they meet the bearing walls of a building. It is normal practice, accordingly, to provide cross beams secured to underside portions of the roof sheets to prevent such spreading. In addition, a ceiling is usually installed to block from view the cross beams and roof rafters or stiffening ribs and also provide the usual insulating air space.
In prefabricated type housing units, the roof may be prefabricated in the form of roof sheets which slant downwardly from a center ridge member. In these constructions, the same problems exist with respect to the gravitational component of force tending to spread the lower ends of the roof sheets and thus exert forces on the upper edges of the bearing walls tending to spread the walls. It would be desirable to provide a more efficient and simplified means for countering this spreading force which not only can be adjusted after the roofing structure is in place, but also can serve additional functions all to the end that more economical assembly is possible, both from the material and labor standpoints.